1. Field of the Invention
The present invention is broadly concerned with farm implements including soil-penetrating coulter units which are designed for high speed application of fertilizers (e.g., ammonia) or other products (e.g., seeds) to soil. More particularly, the invention is concerned with such implements, and the coulter units forming a part thereof, wherein the coulter units are provided with a gauge assembly to limit the depth of penetration of the coulter blade into soil, while also serving to minimize soil disruption. Preferably, the gauge assembly includes a pair of continuous, shiftable loops astride the coulter blade and arranged to engage the surface of the earth as the coulter unit traverses a field.
2. Description of the Prior Art
A variety of farm tillage implements have been provided in the past for seed planting or incorporation of various liquid preparations and/or other products into the soil. Generally, these types of implements include a plurality of rotatably mounted, disc-shaped coulter blades, which form slits or trenches in the soil as the implement is pulled through a field. In fertilizer or seeding applications, each coulter blade is typically trailed by a shoe or knife supporting a tube through which liquid fertilizer, seed or the like is incorporated into the soil. An implement of this character is described in U.S. Pat. No. 4,656,957.
A problem with conventional coulter implements, and especially those used in the context of soil fertilization, is the inability to rapidly pull the implements through the soil. Relatively high speed operation of such implements results in two adverse effects. First, such operation tends to unacceptably disrupt or “throw up” the soil adjacent the coulter blades leaving the field in a poor condition and making subsequent field operations more difficult. Second, because of these disruptions, the injected liquid fertilizer has an opportunity to vaporize into the atmosphere, such that the value of the fertilizer is lost.
There is accordingly a need in the art for an improved coulter design which overcomes the aforementioned problems and permits high speed and therefore more efficient field tillage operations, including fertilization and seeding.
U.S. Pat. No. 4,716,971 describes a tillage implement having coulter units, wherein a pair of driven, blade-cleaning belts are positioned on opposite sides of and in engagement with each coulter blade. However, each blade set is located adjacent the upper extent of the associated coulter blade, and therefore the belts are not designed for contact with the soil.
Other references of interest include U.S. Pat. Nos. 197,204, 709,741, 1,062,169, 2,391,910, 2,912,944, 5,626,196, 7,481,171; U.S. Published Patent Application No 2010/0282480; and non-patent literature Agronimic Row Crops—Cultivator Components, found on-line at http://www.sare.org/publications/steel/pg26.htm, (Date Accessed Dec. 29, 2010).